Peterson built this kit based on the U.S. Army specifications for their breacher teams. They are all 0.025″ thick “government steel”, which must be a version ASTM 301 cold rolled steel. I CAN tell you that the government steel is very durable and will take a LOT of abuse before failing. The little kit fits nicely into the leather case and the cost, direct from ThinkPeterson.com at a rather pricey $57. If you live in Europe or attack a lot of paracentric or narrow keyways, this kit may be a bit thick for routine use, so I’d recommend looking at the same picks in 0.015″ or 0.018″ thickness instead.